A water treatment apparatus removes impurities in water by adsorbing and removing cations or anions using an ion exchange resin. There are cases where an ion exchange membrane where a cation exchange group is disposed on one surface and an anion exchange group is disposed on the other surface is used in a water treatment apparatus (for example, refer to PTL 1).
Textured membranes where peaks and troughs are disposed at intervals are known as the ion exchange membrane of the water treatment apparatus, (for example, refer to PTL 1). FIG. 13 is a schematic diagram which shows a schematic configuration of the textured membrane disclosed in PTL 1.
As shown in FIG. 13, a textured membrane 105 disclosed in PTL 1 has a cation exchange layer 101 and an anion exchange layer 102 adjacent to the cation exchange layer 101, in which peaks 103 and troughs 104 are disposed at intervals. Since the surface area of a membrane is increased by the peaks 103 and the troughs 104 which are formed on the textured membrane 105, in a case of supplying water which includes hard components to the textured membrane 105, it is possible to increase the adsorption speed of the hard components. In addition, regarding the peaks 103 and the troughs 104 of the textured membrane 105, in a case of using a plurality of laminated textured membranes 105, it is possible to suppress pressure loss to be low since the path of the treatment water is formed between the peaks 103 and the troughs 104 as shown by an arrow 106.
In addition, PTL 1 discloses an electrochemical cell where an electrode 107 and an electrode 108 are disposed on both sides of the textured membrane 105. In the electrochemical cell disclosed in PTL 1, H+ and OH− are generated by dissociating water at an interface 109 of the cation exchange layer 101 and the anion exchange layer 102 by applying voltage to both electrodes in the presence of water. It is possible to regenerate the cation exchange layer 101 and the anion exchange layer 102 by substituting the H+ and OH−, and the cations and anions which are adsorbed in the cation exchange layer 101 and the anion exchange layer 102. Therefore, in the electrochemical cell disclosed in PTL 1, regeneration using a chemical agent is not necessary as in the related art.
However, even with the electrochemical cell which has the textured membrane 105 disclosed in PTL 1, since water flows only on a surface of the textured membrane 105 and only a portion which is exposed on a surface of the cation exchange layer 101 and the anion exchange layer 102 reacts, there is a first problem in that the ability to adsorb the hard components using the cation exchange layer 101 and the anion exchange layer 102 is not sufficiently obtained.
In addition, even with a water treatment apparatus which uses the textured membrane 105 disclosed in PTL 1, there is still room for the improvement from the point of view of making the flow of water in the apparatus uniform. In detail, in a case of arranging the textured membrane 105 by setting the direction of the arrow 106 to the vertical direction, there is a concern that a path which is formed between the peaks 103 and the troughs 104 will be crushed due to the shape of the membrane being changed under the weight of the textured membrane 105 itself and that the pressure loss will be large. In addition, when the path is crushed, since water is not able to flow in the path, there is a second problem in that there is a concern in that it is not possible to sufficiently adsorb the hard components.